Image forming apparatus, condition determination method, and computer program

ABSTRACT

Disclosed is an image forming apparatus, which may execute a job including printing an image. The disclosed image forming apparatus may include: a printer; a detector that may detect a property of a printing paper sheet, the printing paper sheet being a paper sheet used by the printer in the printing; and a determinator that may, on the basis of the property detected by the detector and a situation of the job, determine conditions for executing the printing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese patent Application No.2018-102239, filed on May 29, 2018, which is incorporated herein byreference in its entirety.

BACKGROUND Technological Field

The present disclosure relates to a technology for determiningconditions of a printer or the like of an image forming apparatus.

Description of the Related Art

As a paper sheet on which an image forming apparatus prints an image,various kinds of paper sheets are used. In order to obtain a higherquality printed matter, it is preferable that the transport speed of apaper sheet, the temperature of a fixing roller or the like is setaccording to a kind of paper sheet.

Therefore, conventionally, an image forming apparatus allows a user toinput a kind of paper sheet, and sets the speed, the temperature or thelike described above according to the input kind.

However, the user often does not know the kind of paper sheet, or mayforget to input the kind. In another case, the user may decide not toinput the kind on purpose because the user finds the input operationtroublesome.

Accordingly, there is proposed a technology in which a sensor fordetecting a kind of paper sheet is provided in an image formingapparatus, and the transport speed, the temperature of a fixing roller,or the like is set according to the kind detected by the sensor.

According to the technology disclosed in JP 2008-225052 A, whether ornot a paper-kind stored value exists is determined at the start in paperfeeding transport operation, and if a stored value exists, the storedvalue is compared with a data range of a paper-kind determination tableso as to determine a paper kind. If no stored value exists, a paper-kinddetector performs measurement. Measured data is stored in a temporarystoring part as a temporarily stored value, the temporarily stored valueis stored in a paper-kind storing part as a paper-kind stored value, anda paper kind is similarly determined. When determination conditions forclearing data are satisfied, a data clear part clears a paper-kindstored value of a paper feeding stage that performs corresponding paperfeeding operation of the paper-kind storing part.

According to the technology disclosed in JP 2007-58084 A, a kind ofrecording material supplied is determined by a sensor, and according toa result of the determination, the control is performed so as to changeconditions such as transport speed, fixing control temperature, and atransfer bias. However, in a case where a detection result falls withina detection boundary region (for example, a boundary between a thinpaper mode and a standard paper mode), a user is made select a desiredsetting.

Conventionally, although the same kind of paper sheets are supplied froma paper feed tray to a printing unit, an error of measurement by asensor, a change in ambient humidity, or the like may cause a detectionresult to differ depending on the timing According to the technologydisclosed in JP 2007-58084 A, in such a case, a user is made select adesired setting. However, the user may find the selecting worktroublesome. Accordingly, it is desirable that a kind be automaticallydetected.

However, for example, although a kind of supplied paper sheets is thickpaper, if it is detected that the kind is standard paper, a malfunctionmay occur in a finisher. In other words, although an upper limit ofthickness that allows stapling is exceeded, the finisher tries stapling.Consequently, there is a possibility that the finisher will fail instapling, which causes the printed matter to be wasted, or causes thefinisher to be damaged. The same applies to a case where post-processingother than stapling is performed.

In another case, although a kind of supplied paper sheets is standardpaper, if it is detected that the kind is thick paper, there is apossibility that the productivity will become lower than that in thecase of the true kind. This is because the transport speed for the thickpaper is often set lower than the transport speed for the standardpaper.

However, the conventional technologies as disclosed in JP 2008-225052 Aand JP 2007-58084 A cannot solve such problems.

SUMMARY

The present disclosure has been made taking such problems intoconsideration, and an object of the present disclosure is, in asituation in which the result of detecting a kind easily changesalthough the same kind of paper sheets is used, to enable an image to beprinted on a paper sheet, or to enable a printed matter to be subjectedto post-processing, more satisfactorily than heretofore.

To achieve the abovementioned object, according to an aspect of thepresent disclosure, an image forming apparatus may execute a jobincluding printing an image. The image forming apparatus may comprise: aprinter; a detector that may detect a property of a printing papersheet, the printing paper sheet being a paper sheet used by the printerin the printing; and a determinator that may, on the basis of theproperty detected by the detector and a situation of the job, determineconditions for executing the printing.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features provided by one or more embodiments of thedisclosure will become more fully understood from the detaileddescription given hereinbelow and the appended drawings which are givenby way of illustration only, and thus are not intended as a definitionof the limits of the present disclosure:

FIG. 1 is a drawing illustrating an example of an external appearance ofan image forming apparatus;

FIG. 2 is a diagram illustrating an example of a hardware configurationof the image forming apparatus;

FIG. 3 is a drawing illustrating an example of a configuration of aprint unit;

FIGS. 4A and 4B are diagrams each illustrating an example of aconfiguration of a water-content sensor;

FIG. 5 is a diagram illustrating an example of a functionalconfiguration of the image forming apparatus;

FIG. 6 is a flowchart illustrating an example of an initial settingprocess flow;

FIG. 7 is a drawing illustrating an example of relationship among basicweight of paper sheet, kinds of paper sheet, and threshold values;

FIG. 8 is a drawing illustrating an example of environment data;

FIG. 9 is a flowchart illustrating an example of an environment changeprocess flow;

FIG. 10 is a drawing illustrating an example of a dispersion allowablerange;

FIGS. 11A and 11B are drawings each illustrating an example of a methodfor calculating a threshold value;

FIG. 12 is a drawing illustrating an example of threshold values forrespective items; and

FIG. 13 is a flowchart illustrating an example of an overall processflow related to a print job.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, one or more embodiments of the present disclosure will bedescribed with reference to the drawings. However, the scope of thedisclosure is not limited to the disclosed embodiments.

FIG. 1 is a drawing illustrating an example of an external appearance ofan image forming apparatus 1. FIG. 2 is a diagram illustrating anexample of a hardware configuration of the image forming apparatus 1.FIG. 3 is a drawing illustrating an example of a configuration of aprint unit 10 i. FIGS. 4A and 4B are diagrams each illustrating anexample of a configuration of a water-content sensor 10 k.

The image forming apparatus 1 shown in FIG. 1 is an apparatus that isgenerally called a “Multi Function Peripheral (MFP)” or a “multifunctionmachine”, and is an apparatus into which functions such as a copyfunction, a PC print function, a facsimile function, a scanning functionand a box function may be integrated.

The PC print function is what is called a function of receiving imagedata from a terminal device through a Local Area Network (LAN) line, andprinting an image on a paper sheet. The PC print function may be calleda “network printer function” or a “network printing function”.

The box function is a function of providing a storage area called a“box”, a “personal box” or the like on a user basis, and allowing eachuser to save and manage image data by using the user's own storage area.A box can also be provided on a group basis so as to be shared amonggroup members. The box is equivalent to a “folder” or a “directory” in apersonal computer.

As shown in FIG. 1 or FIG. 2, the image forming apparatus 1 is formed bya main Central Processing Unit (CPU) 10 a, a Random Access Memory (RAM)10 b, a Read Only Memory (ROM) 10 c, an auxiliary storage device 10 d,an operation panel 10 e, a Network Interface Card (NIC) 10 f, a modem 10g, a scan unit 10 h, a print unit 10 i, a finisher unit 10 j, awater-content sensor 10 k, a paper-kind sensor 10 m, and the like.

The operation panel 10 e is formed by a key input part, a touch paneldisplay, and the like.

The key input part is what is called a hardware keyboard, and is formedby ten-keys, a start key, a stop key, function keys, and the like.

The touch panel display displays, for example, a screen for giving auser a message or an instruction, a screen for allowing the user toinput a kind of processing and processing conditions thereof, and ascreen for showing a result of processing executed by the main CPU 10 aor the like.

The NIC 10 f communicates with a terminal device or a server through acommunication line by using a protocol such as Transmission ControlProtocol/Internet Protocol (TCP/IP).

The modem 10 g exchanges image data with a facsimile terminal through apublic telephone line by using a protocol such as G3.

The scan unit 10 h reads an image printed on a medium that is set in anAuto Document Feeder (ADF) or on platen glass, and then generates imagedata.

The print unit 10 i prints not only an image read by the scan unit 10 h,but also an image shown in image data received from other devices, on apaper sheet. A case where a tandem-type color print engine is used asthe print unit 10 i will be described below as an example.

As shown in FIG. 3, the print unit 10 i is formed mainly by includes animaging part 2, and a transport part 3.

The imaging part 2 is formed by imaging units 21, an intermediatetransfer unit 23, and the like.

The imaging units 21 are provided for respective Y (yellow), M(magenta), C (cyan) and K (black) colors, and form toner images of therespective colors.

Here, by taking the yellow imaging unit 21 as an example, a mechanism ofthe imaging unit 21 will be described.

The imaging unit 21 is formed by a cartridge 211, a photoreceptor drum212, an electric charger 213, a laser scan optical unit 214, adeveloping device 215, and the like.

An yellow toner and a carrier are stored in the cartridge 211 by beingmixed at a constant ratio.

The electric charger 213 charges the photoreceptor drum 212. The laserscan optical unit 214 performs exposure according to a print targetimage, thereby generating a yellow electrostatic latent image on thephotoreceptor drum 212.

In addition, the developing device 215 puts the yellow toner stored inthe cartridge 211 on the photoreceptor drum 212 so as to form a yellowtoner image on the photoreceptor drum 212.

The magenta, cyan and black cartridges 211 or the magenta, cyan andblack developing devices 215 each play a role similar to that of theyellow cartridge 211 or the yellow developing device 215, and form themagenta, cyan and black toner images respectively.

The intermediate transfer unit 23 synthesizes the yellow, magenta, cyanand black toner images into one toner image as described below.

The intermediate transfer unit 23 is formed by primary transfer rollers231, an intermediate transfer belt 232, and the like.

The primary transfer rollers 231 are provided corresponding to therespective yellow, magenta, cyan and black colors so as to face therespective color photoreceptor drums 212 across the intermediatetransfer belt 232.

Subsequently, electric fields generated by the respective color primarytransfer rollers 231 cause the respective color toner images to betransferred to the intermediate transfer belt 232. As the result, thetoner image is synthesized.

The transport part 3 is formed by a paper feed tray 31, a paper feedroller 32, a resist roller 33, a secondary transfer roller 34, a heatingroller 35, a pressure roller 36, a paper discharge roller 37, and thelike. The transport part 3 transports a paper sheet as described below,and fixes the toner image, which has been synthesized on theintermediate transfer belt 232, to a paper sheet.

The paper feed tray 31 stores one or more paper sheets 40, each of whichis subjected to image printing. Two or more paper feed trays 31 may beprovided. In the present embodiment, two paper feed trays 31 areprovided. Hereinafter, the paper feed trays 31 may be distinctivelyreferred to as a “first paper feed tray 31A” and a “second paper feedtray 31B” in order from the top. In addition, it is assumed that thesize of paper sheets set in the first paper feed tray 31A differs fromthe size of paper sheet sets in the second paper feed tray 31B. Forexample, A4 size paper sheets are set in the first paper feed tray 31A,and A3 size paper sheets are set in the second paper feed tray 31B.

The paper feed trays 31 are provided with the paper feed rollers 32respectively. The paper feed rollers 32 transport the paper sheet 40from the respective paper feed trays 31 to the resist roller 33 one byone.

When the paper sheet 40 has been transported by each of the paper feedrollers 32, the resist roller 33 temporarily stops the paper sheet 40,and feeds the paper sheet 40 to the secondary transfer roller 34 in thepredetermined timing.

The secondary transfer roller 34 transfers the toner image, which hasbeen synthesized on the intermediate transfer belt 232, onto the papersheet 40 fed from the resist roller 33.

The heating roller 35 heats the paper sheet 40 on which the toner imagehas been transferred. The pressure roller 36 pressurizes the paper sheet40 on which the toner image has been transferred. This causes the tonerimage to be fixed on the paper sheet 40. In general, the heating roller35 and the pressure roller 36 may be called “fixing roller”.

The paper discharge roller 37 feeds the paper sheet 40 on which thetoner image has been fixed to the finisher unit 10 j.

Returning to FIG. 2, the finisher unit 10 j subjects the paper sheet onwhich the image has been printed by the print unit 10 i, that is to say,a printed matter, to finishing processing to process the paper sheet.Specifically, the finisher unit 10 j is formed by a staple device, apunch device, a paper folding device, and the like. In addition, as thefinishing processing, one or more of the following processing isperformed: processing of binding paper sheets by the staple device(hereinafter referred to as “staple processing”); processing ofproviding paper sheets with punched holes (hereinafter referred to as“punched hole processing”); and processing of folding paper sheets(hereinafter referred to as “fold finishing performing”).

When the paper sheet 40 is transported to the secondary transfer roller34 by the resist roller 33, the water-content sensor 10 k measures thewater content of the paper sheet 40. In the present embodiment, acapacitive touch sensor is used as the water-content sensor 10 k.

For example, as shown in FIG. 4A, the water-content sensor 10 k isformed by a microcomputer 10 k 1, a touch electrode 10 k 2, a panel 10 k3, a ground plane 10 k 4, and the like.

The panel 10 k 3 and the ground plane 10 k 4 are provided in such amanner that the transport path 39 of the paper sheet 40, which extendsfrom the resist roller 33 to the secondary transfer roller 34, is putbetween the panel 10 k 3 and the ground plane 10 k 4. The touchelectrode 10 k 2 is provided on the back surface of the panel 10 k 3.

The microcomputer 10 k 1 calculates water content on the basis of avoltage value input from the touch electrode 10 k 2. The voltage valuedepends on capacitance between the touch electrode 10 k 2 and the groundplane 10 k 4.

Therefore, when the paper sheet 40 passes therebetween as shown in FIG.4B, a voltage value corresponding to the paper sheet 40 is input intothe microcomputer 10 k 1. Subsequently, the microcomputer 10 k 1calculates the water content of the paper sheet 40 on the basis of theinput voltage value.

Before the paper sheet 40 is transported to the secondary transferroller 34 by the resist roller 33, the paper-kind sensor 10 m measuresthe basic weight, thickness or the like of the paper sheet 40, anddetermines a kind of paper sheet 40 on the basis of the measured basicweight, thickness or the like. The paper-kind sensor 10 m is, forexample, an optical sensor for detecting transmitted light that hastransmitted through paper.

Returning to FIG. 2, the ROM 10 c or the auxiliary storage device 10 dstores a print job control program 10P. The print job control program10P is a program for executing a job that is accompanied with printing.The job accompanied with printing is generically called “print job”.

As an example of the print job, the print job includes: a copy job (ajob of scanning an image from a paper sheet of an original document, andprinting the image on other paper sheets); a PC print job (a job ofreceiving print data of Page Description Language (PDL) from a terminaldevice, and printing an image on a paper sheet on the basis of the printdata); and a facsimile receiving job (job of receiving facsimile datafrom a facsimile terminal, and printing an image on a paper sheet on thebasis of the facsimile data).

FIG. 5 is a diagram illustrating an example of a functionalconfiguration of the image forming apparatus 1. FIG. 6 is a flowchartillustrating an example of an initial setting process flow. FIG. 7 is adrawing illustrating an example of relationship among basic weight ofpaper sheet, kinds of paper sheet, and threshold values. FIG. 8 is adrawing illustrating an example of environment data 5C. FIG. 9 is aflowchart illustrating an example of an environment change process flow.FIG. 10 is a drawing illustrating an example of a dispersion allowablerange 60. FIGS. 11A and 11B are drawings each illustrating an example ofa method for calculating a threshold value xh. FIG. 12 is a drawingillustrating an example of threshold values xh1 to xh6 for respectiveitems.

According to the print job control program 10P, a job data generationpart 101, a job start control part 102, an environment initial settingpart 103, an environment changing part 104, a job data deletion part105, a job data storage part 106, a measured data storage part 107, andan environment data storage part 108 and the like, which are shown inFIG. 5, are realized in the image forming apparatus 1.

Every time a user instructs a print job, the job data generation part101 performs, as below according to a kind of the print job, processingof generating data used to print an image.

When a user instructs a copy job, the user sets a paper sheet of anoriginal document in the ADF or platen glass of the scan unit 10 h, andinputs a predetermined command into the operation panel 10 e.

As the result, the job data generation part 101 causes the scan unit 10h to execute processing of reading an image from the set paper sheet togenerate image data, and converts the generated image data into YMCKimage data. Subsequently, this YMCK image data and data indicatingprinting or finishing conditions are stored in the job data storage part106 as job data 5A by being associated with the date and time at whichthe command has been input.

It should be noted that as an example of the printing conditions, therecan be mentioned a size (paper size) of the paper sheet 40 on which animage is printed, image quality of the image, whether to print the imagein color or monochrome, the number of copies, and the like. As anexample of the finishing conditions, there can be mentionedpresence/absence of staple processing, presence/absence of punched holeprocessing, presence/absence of fold finishing performing, and the like.

Alternatively, when a user instructs a PC print job, the user preparesdata of a printing target document in the terminal device, and inputsthe PC print instruction into the terminal device. As the result, theterminal device converts the data into PDL print data, and transmits thePDL print data to the image forming apparatus 1.

When the job data generation part 101 receives the print data from theterminal device, the job data generation part 101 converts this printdata into YMCK image data. Subsequently, this YMCK image data and dataindicating printing or finishing conditions are stored in the job datastorage part 106 as the job data 5A by being associated with the dateand time at which the print data has been received.

Alternatively, when an incoming call is received from the facsimileterminal, with the result that facsimile data is received from thefacsimile terminal, the job data generation part 101 converts thisfacsimile data into binary image data. Subsequently, this image data anddata indicating printing or finishing conditions are stored in the jobdata storage part 106 as the job data 5A by being associated with thedate and time at which the facsimile data has been received.

When the print unit 10 i and the finisher unit 10 j are brought into anidling state, the job start control part 102 reads data, the associateddate and time of which is the earliest, from among the job data 5Astored in the job data storage part 106, and controls the print unit 10i, the finisher unit 10 j or the like in such a manner that the printjob is executed on the basis of the read job data 5A.

In this case, which of the first paper feed tray 31A and the secondpaper feed tray 31B supplies the paper sheet 40 is determined on thebasis of the paper size indicated by the job data 5A. In other words, asupplier of the paper sheet 40 is determined.

Before an image is printed on the paper sheet 40, the followingprocessing is executed by the environment initial setting part 103 orthe environment changing part 104 as appropriate.

In a case where the paper sheet 40 is supplied from the paper feed tray31 as the supplier for the first time, the environment initial settingpart 103 sets respective environments of the print unit 10 i and thefinisher unit 10 j according to a kind of the paper sheet 40 by usingsteps shown in FIG. 6.

When the first paper sheet 40 is carried out from the paper feed tray31, the environment initial setting part 103 causes the water-contentsensor 10 k to measure water content of the paper sheet 40 (#701 of FIG.6), and causes the paper-kind sensor 10 m to determine a kind of thepaper sheet 40 (#702). Measured data 5B is generated, and is then storedin the measured data storage part 107 (#703). In a case where oldmeasured data 5B is already stored in the measured data storage part107, this measured data 5B is deleted.

In the measured data 5B, the measured water content, and the basicweight measured when the kind is determined, are indicated as measuredwater content Rs and measured basic weight Xs respectively. Moreover, anidentifier of the paper feed tray 31 is indicated.

It should be noted that at the beginning of the operation of the imageforming apparatus 1, the measured data 5B is not stored in theenvironment initial setting part 103.

A case where the paper-kind sensor 10 m determines a kind on the basisof the basic weight will be described below as an example. In general,the basic weight of a paper sheet differs depending on a kind. A casewhere six kinds of paper sheets (“standard paper_E1”, “standardpaper_E2”, “standard paper_E3”, “thick paper_F1”, “thick paper_F2”, and“thick paper_F3” in order of increasing basic weight under predeterminedconditions) are used in the image forming apparatus 1 will be describedbelow as an example.

As threshold values for discriminating these six kinds of paper sheets,threshold values xa, xb, xc, xd and xe are stored in the paper-kindsensor 10 m beforehand Hereinafter, these threshold values may bedesignated as “default threshold values”. The threshold values xa, xb,xc, xd and xe are fixed values.

In addition, if Sa<xa, the paper-kind sensor 10 m determines that thekind of the paper sheet 40 is standard paper_E1. Where “Sa” is the basicweight measured by the paper-kind sensor 10 m. If xa≤Sa<xb, thepaper-kind sensor 10 m determines that the kind of the paper sheet 40 isstandard paper_E2. If xb≤Sa<xc, the paper-kind sensor 10 m determinesthat the kind of the paper sheet 40 is standard paper_E3. If xc≤Sa<xd,the paper-kind sensor 10 m determines that the kind of the paper sheet40 is thick paper_F1. If xd≤Sa<xe, the paper-kind sensor 10 m determinesthat the kind of the paper sheet 40 is thick paper_F2. If xe≤Sa, thepaper-kind sensor 10 m determines that the kind of the paper sheet 40 isthick paper_F3.

In other words, on the assumption that the X-axis represents the basicweight, and the Y-axis represents kinds, a linear function (Y=g(X)=m×X+n. . . (1)) is set in the paper-kind sensor 10 m beforehand Here, m and nare both constants.

Moreover, Y ranges for the respective kinds are set according to thefollowing inequalities (2_1) to (2_6).Standard paper_E1: Y<g(xa)  (2_1)Standard paper_E2: g(xa)≤Y<g(xb)  (2_2)Standard paper_E3: g(xb)≤Y<g(xc)  (2_3)Thick paper_F1: g(xc)≤Y<g(xd)  (2_4)Thick paper_F2: g(xd)≤Y<g(xe)  (2_5)Thick paper_F3: g(xe)≤Y  (2_6)

In addition, by substituting the measured basic weight into this linearfunction, the paper-kind sensor 10 m is capable of calculating aY-value, and consequently is capable of determining a kind of the papersheet 40 on the basis of the inequalities (2_1) to (2_6).

Incidentally, for each kind of paper sheet, a preferable environment ofeach of the print unit 10 i and the finisher unit 10 j is knownbeforehand. The environment data storage part 108 stores beforehandenvironment data 5C indicating, on a kind basis, a preferableenvironment of each of the print unit 10 i and the finisher unit 10 j.

Specifically, as shown in FIG. 8, the environment data 5C indicates, ona kind basis, condition values of items of: preferable fixingtemperature; preferable image parameter; preferable transport speed;maximum number of stapled sheets; maximum number of punched sheets; andmaximum number of folded sheets.

The “preferable fixing temperature” is a temperature that should bemaintained by the heating roller 35 so as to heat that kind of papersheet. The “preferable image parameter” is a preferable parameterrelated to various kinds of matters of an image to be printed on thatkind of paper sheet (for example, an increase and a decrease in coveragerate or density). The “preferable transport speed” is a speed that issuitable for transporting that kind of paper sheet.

The “maximum number of stapled sheets” is the maximum number of sheets(that kind of paper sheets) that can be stapled all together. The“maximum number of punched sheets” is the maximum number of sheets (thatkind of paper sheets) that can be punched all together. The “maximumnumber of folded sheets” is the maximum number of sheets (that kind ofpaper sheets) that can be subjected to fold finishing processing alltogether.

Return to FIG. 5, the environment initial setting part 103 determines,on the basis of the environment data 5C, the respective environments ofthe print unit 10 i and the finisher unit 10 j, the environmentscorresponding to the determined kind (#704), and sets the environmentsin the print unit 10 i and the finisher unit 10 j respectively (#705).

For example, in a case where the determined kind is thick paper F1, theenvironment initial setting part 103 sets environments in the step #705as described below. The heating roller 35 is controlled in such a mannerthat the temperature is maintained at T4[° C.] or more. Each of theimaging units 21 is controlled in such a manner that the coverage ratebecomes standard U4[%]. The transport part 3 is controlled in such amanner that the paper sheet 40 is transported at P4 [m/s]. The finisherunit 10 j is controlled in such a manner that staple processing for thepaper sheets 40, the number of sheets of which exceeds Ma4 [sheets], isprohibited. The finisher unit 10 j is controlled in such a manner thatpunched hole processing for the paper sheets 40, the number of sheets ofwhich exceeds Mb4 [sheets], is prohibited. The finisher unit 10 j iscontrolled in such a manner that fold finishing performing for the papersheets 40, the number of sheets of which exceeds Mc4 [sheets], isprohibited.

Further, print processing or finishing processing is performed by theprint unit 10 i or the finisher unit 10 j in the environment set by theenvironment initial setting part 103.

Meanwhile, in a case where the paper sheet 40 has already been suppliedfrom the paper feed tray 31 as the supplier, and immediately after apower source has been switched on, or immediately after the paper feedtray 31 has been closed, the environment changing part 104 sets therespective environments of the print unit 10 i and the finisher unit 10j according to steps shown in FIG. 9.

Immediately after the power source has been switched on, or immediatelyafter the paper feed tray 31 has been closed, when the first paper sheet40 is carried out, the environment changing part 104 causes thewater-content sensor 10 k to measure the water content of the papersheet 40 (#711 of FIG. 9), and causes the paper-kind sensor 10 m todetermine a kind of the paper sheet 40 (#712). It should be noted thatwhen the kind is determined, the basic weight of the paper sheet 40 ismeasured.

According to the water content and the basic weight that have beenmeasured last time, the environment changing part 104 determines thedispersion allowable range 60 as shown in FIG. 10 (#713). It should benoted that the water content and the basic weight are the measured watercontent Rs and the measured basic weight Xs that are shown in themeasured data 5B indicated by an identifier of the paper feed tray 31.The measured data 5B is stored in the measured data storage part 107.

The dispersion allowable range 60 is a rectangular area, and the upperside, the lower side, the right side and the left side are spaced awayfrom a point Qs by distances h1, h2, w1 and w2 respectively. AY-coordinate value of the point Qs is determined by substituting themeasured basic weight Xs into a variable X of the equation (1) (refer toFIG. 7). In other words, the Y-coordinate value of the point Qs isg(Xs).

At least one of the distances h1, h2, w1 and w2 is set at a longer valuewith the increase in the water content, that is to say, the measuredwater content Rs, that has been measured last time. In the presentembodiment, the respective distances are set by the following equations(3_1) to (3_4). Here, p1 to p4 and q1 to q4 are all positive constants.Distance h1=p1×Rs+q1  (3_1)Distance h2=p2×Rs+q2  (3_2)Distance w1=p3×Rs+q3  (3_3)Distance w2=p4×Rs+q4  (3_4)

The environment changing part 104 determines whether or not the point Qtfalls within the dispersion allowable range 60 (#714). An X-coordinatevalue of the point Qt is the basic weight measured in the step #712. AY-coordinate value of the point Qt is determined by substituting thebasic weight measured in the step #712 into the variable X of theequation (1). In other words, if the basic weight measured in the step#712 is “Xt”, the Y-coordinate value of the point Qt is g(Xt).

In a case where the point Qt does not fall within the dispersionallowable range 60 (No in #715), as with the steps #704 to #705 of FIG.5, the environment changing part 104 determines respective environmentsof the print unit 10 i and the finisher unit 10 j on the basis ofenvironment data 5C according to the kind determined in the step #712(#716), and sets the environments in the print unit 10 i and thefinisher unit 10 j respectively (#717).

Meanwhile, in a case where the point Qt falls within the dispersionallowable range 60 (Yes in #715), the environment changing part 104determines which matter should have the first priority among theavoidance of damage of a device, the image quality, and the productivityas described below (#718).

The environment changing part 104 calculates the number of jobs N1 andthe number of current job sheets N2. The “number of jobs N1” is thenumber of print jobs that are waiting for print processing, and is thenumber of job data 5A stored in the job data storage part 106. The“number of current job sheets N2” is the number of paper sheets used ina print job that is currently executing print processing. The number ofcurrent job sheets N2 can be determined on the basis of conditions orthe like indicated in the job data 5A of the print job. For example, ina case where intensive printing is “OFF” and printing surface is “singleside”, a determination has only to be made that the product of thenumber of pages and the number of copies is the number of current jobsheets N2.

In addition, in a case where the number of jobs N1 is a threshold valueM1 or more and the number of current job sheets N2 is smaller than athreshold value M2, the environment changing part 104 determines that amatter having the first priority is the productivity. In a case wherethe number of jobs N1 is smaller than the threshold value M1 and thenumber of current job sheets N2 is smaller than the threshold value M2,it is determined that a matter having the first priority is the imagequality. In a case where the number of current job sheets N2 is thethreshold value M2 or more irrespective of a value of the number of jobsN1, it is determined that a matter having the first priority is theavoidance of damage of a device.

According to the determined matter having the first priority, theenvironment changing part 104 determines threshold values xh for therespective items of: the preferable fixing temperature; the preferableimage parameter; the preferable transport speed; the maximum number ofstapled sheets; the maximum number of punched sheets; and the maximumnumber of folded sheets (#719). The threshold value xh is used as analternative to any of the threshold values xa, xb, xc, xd and xe shownin FIG. 7. How to use the threshold value xh will be described later.The respective threshold values of the preferable fixing temperature,the preferable image parameter, the preferable transport speed, themaximum number of stapled sheets, the maximum number of punched sheetsand the maximum number of folded sheets will be described below indistinction from the “threshold value xh1”, the “threshold value xh2”,the “threshold value xh3”, the “threshold value xh4”, the “thresholdvalue xh5”, and the “threshold value xh6”.

Here, how to determine the threshold values xh will be described bytaking, as an example, a case where the dispersion allowable range 60extends across the vertical axis L passing through “X=xc”, that is tosay, the vertical axis that forms the border between the standardpaper_E3 and the thick paper_F1.

In a case where the matter having the first priority is the avoidance ofdamage of a device, as shown in FIG. 11A, the environment changing part104 determines the threshold values xh to be “xc−w3” for the preferabletransport speed, the maximum number of stapled sheets, the maximumnumber of punched sheets, and the maximum number of folded sheets, amongthe above-described items. In other words, the threshold values xh3,xh4, xh5 and xh6 are determined to be “xc−w3”. However, it is preferablethat w3≤w1. It should be noted that a different value may be used as thedistance w3 on an item basis. The same applies hereinafter. This makesit easy to apply the environment corresponding to the thick paper F1 forthese four items.

Meanwhile, for the preferable fixing temperature and the preferableimage parameter, the environment changing part 104 determines thethreshold value xh to be the threshold value xc. In other words, thethreshold values xh1 and xh2 are determined to be the threshold valuexc.

Alternatively, in a case where the matter having the first priority isthe image quality, as shown in FIG. 11A, the environment changing part104 determines the threshold values xh to be “xc−w3” for the preferablefixing temperature and the preferable image parameter. In other words,the threshold values xh1 and xh2 are determined to be “xc−w3”. Thismakes it easy to apply the environment corresponding to the thickpaper_F1 for these two items.

Meanwhile, for the preferable transport speed, the maximum number ofstapled sheets, the maximum number of punched sheets, and the maximumnumber of folded sheets, the environment changing part 104 determinesthe threshold value xh to be the threshold value xc. In other words, thethreshold values xh3, xh4, xh5 and xh6 are determined to be thethreshold value xc.

Alternatively, in a case where the matter having the first priority isthe productivity, as shown in FIG. 11B, the environment changing part104 determines the threshold value xh to be “xc+w4” for the preferabletransport speed. In other words, the threshold value xh3 is determinedto be “xc+w4”. However, it is preferable that w4≤w2. This makes it easyto apply the environment corresponding to the standard paper_E3 for thepreferable transport speed. For the other items, the threshold value xhis determined to be the threshold value xc. In other words, thethreshold values xh1, xh2, xh4, xh5 and xh6 are determined to be thethreshold value xc. It should be noted that for the preferable fixingtemperature as well, the threshold value xh may be determined to be“xc+w4”.

On the basis of the environment data 5C (refer to FIG. 8), theenvironment changing part 104 determines environments for the respectiveitems by using the respective threshold values xh as an alternative todefault threshold values included in the dispersion allowable range 60(#720). In other words, in the examples of FIGS. 11A and 11B, respectiveenvironments of the preferable fixing temperature, the preferable imageparameter, the preferable transport speed, the maximum number of stapledsheets, the maximum number of punched sheets and the maximum number offolded sheets are determined by using the threshold values xh1, xh2,xh3, xh4, xh5 and xh6 as an alternative to the default threshold valuesxc.

For example, it is assumed that as the result of the processing in thestep #719, as shown in FIG. 12, the threshold values xh1 and xh2 aredetermined to be “xc−w3”, the threshold values xh3, xh4, xh5 and xh6 aredetermined to be “xc”, and g(Xt) is “xc−w3” or more and is smaller than“xc”.

In this case, if “xh1” is used as an alternative to “xc” in each of theinequalities (2_3) and (2_4), g(Xt) satisfies the inequality (2_4)between both of the inequalities. The same applies when “xh2” is used.

Accordingly, for a matter related to the heating roller 35 and an imageto be printed (for example, an increase and a decrease in coverage rate,density or the like), the environment changing part 104 determines anenvironment corresponding to the thick paper_F1. In other words, T4[°C.] and U4[%] indicated by the environment data 5C are determined.

In addition, if “xh3” is used, g(Xt) satisfies the inequality (2_4)between both of the inequalities. The same applies when each of “xh4”,“xh5” and “xh6” is used.

Accordingly, with respect to the transport speed by the transport part3, the upper limit of the number of sheets for the staple processing,the upper limit of the number of sheets for the punched hole processing,and the upper limit of the number of sheets for the fold finishingprocessing, the environment changing part 104 determines the environmentcorresponding to the standard paper_E3. In other words, P3 [m/s], Ma3[sheets], Mb3 [sheets], and Mc3 [sheets] indicated by the environmentdata 5C are determined.

In addition, the environment changing part 104 controls the print unit10 i and the finisher unit 10 j in such a manner that the determinedenvironments for the respective items are set (#721).

Subsequently, print processing or finishing processing is performed bythe print unit 10 i or the finisher unit 10 j in the environment set bythe environment changing part 104.

The job data deletion part 105 deletes the job data 5A of the completedprint job from the job data storage part 106.

FIG. 13 is a flowchart illustrating an example of an overall processflow related to a print job.

The overall process flow of the image forming apparatus 1 will bedescribed below with reference to the flowchart.

On the basis of the print job control program 10P, the image formingapparatus 1 executes processing according to steps shown in FIG. 13.

When a print job is instructed or print data is received from theterminal device (Yes in #731 of FIG. 13), the image forming apparatus 1generates the job data 5A, and then stores the job data 5A in the jobdata storage part 106 (#732).

In a case where although a print job is not being executed (No in #733),one or more of the job data 5A is stored in the job data storage part106 (Yes in #734), the image forming apparatus 1 starts a print job onthe basis of the job data 5A that has been stored in the earliest timing(#735).

In a case where the paper feed tray 31 that is the supplier of the papersheet 40 is used for the first time (Yes in #736), the image formingapparatus 1 sets respective environments of the print unit 10 i and thefinisher unit 10 j according to a kind of the paper sheet 40 using thesteps shown in FIG. 6 (#737). Subsequently, the image forming apparatus1 performs print processing or finishing processing under theenvironment.

If not (No in #736), the image forming apparatus 1 performs printprocessing or finishing processing under the environment that has beenmost recently set (#738).

When the paper feed tray 31 is opened and is then closed irrespective ofwhether or not a print job is being executed (Yes in #739), the imageforming apparatus 1 sets the respective environments of the print unit10 i and the finisher unit 10 j again according to the water content ofthe paper sheet 40, the number of jobs N1, the number of current jobsheets N2 and the like using the steps shown in FIG. 9 (#740). In a casewhere the power source is switched on again as well, the environmentsare similarly set again.

When the print job is completed (Yes in #741), the image formingapparatus 1 deletes the job data 5A of the print job from the job datastorage part 106 (#742).

While the service is continued (Yes in #743), the image formingapparatus 1 executes the processing of the step #732, the processing ofthe step #737, the processing of the step #738, the processing of thestep #740, and the processing of the step #742 as appropriate.

According to the present embodiment, in a situation in which the resultof detecting a kind easily changes although the same kind of paper sheetis used, an image can be printed on a paper sheet, or a printed mattercan be subjected to post-processing, more satisfactorily thanheretofore.

In the present embodiment, the environment changing part 104 executesthe processing shown in FIG. 9 immediately after the power source hasbeen switched on or immediately after the paper feed tray 31 has beenclosed. However, the processing may be executed in other timings too.For example, the processing may be executed at the time of firstprinting after the lapse of the predetermined time every day.Alternatively, the processing may be executed every time a print job isnewly added. Alternatively, the processing may be executed every time aprint job is completed or canceled.

In the present embodiment, the environment changing part 104 obtains thenumber of paper sheets (the number of current job sheets N2), which areused in a print job that is executing print processing, as informationrelated to the volume of paper sheets used for this print job. However,other information may be obtained as the volume information. Forexample, the sum total of thicknesses of all paper sheets used for thisprint job may be obtained.

In the present embodiment, although the microcomputer 10 k 1 calculatesthe water content, the water content may be determined by the main CPU10 a. In addition, although the paper-kind sensor 10 m measures thebasic weight or thickness of the paper sheet 40, a kind of paper sheetmay be determined by the main CPU 10 a.

In the present embodiment, although the environment changing part 104determines the size of the dispersion allowable range 60 on the basis ofthe water content, the environment changing part 104 may determine thesize of the dispersion allowable range 60 on the basis of thetemperature or humidity of a room in which the image forming apparatus 1is installed. Alternatively, the size of the dispersion allowable range60 may be determined on the basis of the temperature or humidity of theprint unit 10 i. For example, the size of the dispersion allowable range60 may be increased with the increase in humidity. In addition, the sizeof the dispersion allowable range 60 may be a fixed value independent ofthe detection by the environment sensor.

In the present embodiment, although the paper-kind sensor 10 mdetermines a kind of paper sheet on the basis of the basic weight, thepaper-kind sensor 10 m may determine the kind of paper sheet further onthe basis of properties other than the basic weight. For example, thesurface roughness (detection by irregular reflection using a camera, aCCD, or an optical sensor) or the thickness (detection using a paperthickness sensor or a displacement sensor) may be detected. In thiscase, threshold values of respective properties have only to be set foreach kind of paper sheet.

Alternatively, besides the light transmittance, a kind of paper sheetmay be determined on the basis of the light reflectance or thetransmittance or reflectance of ultrasonic waves.

In the present embodiment, the environment changing part 104 determinesthe threshold value xh1 for determining the temperature (that is to say,the fixing temperature) of the heating roller 35 by the number of jobsN1 and the number of current job sheets N2. However, the threshold valuexh1 may be determined further on the basis of the time (the printingtime) required for print processing of a print job that is currentlybeing executed. For example, the threshold value xh1 may be decreasedwith the increase in the printing time. Alternatively, the thresholdvalue xh1 may be determined according to a state in which the paper feedtray 31 is connected to the main body of the image forming apparatus 1,or according to a connection state of the finisher unit 10 j.

In the present embodiment, the environment changing part 104unconditionally sets the newly determined environment in the print unit10 i or the finisher unit 10 j. However, the environment changing part104 may allow a user to select either to set the newly determinedenvironment, or to keep the environment that has been determined by theenvironment initial setting part 103 or the environment changing part104 last time.

In the present embodiment, the method for determining conditions of therespective items is changed by changing how to calculate the thresholdvalues xh. However, the method may be changed by preparing a pluralityof functions or tables, and by using the functions or tables properly.

Besides the above, the configuration of the whole or part of the imageforming apparatus 1, the processing contents, the order of processing,the configuration of data, and the like can be changed as appropriateaccording to the gist of the present disclosure.

Although embodiments of the present disclosure have been described andillustrated in detail, the disclosed embodiments are made for purposesof illustration and example only and not limitation. The scope of thepresent disclosure should be interpreted by terms of the appendedclaims.

As used throughout this application, the words “can” and “may” are usedin a permissive sense (i.e., meaning having the potential to), ratherthan the mandatory sense (i.e., meaning must). The words “include”,“including”, and “includes” and the like mean including, but not limitedto. As used herein, the singular form of “a”, “an”, and “the” includeplural references unless the context clearly dictates otherwise. Asemployed herein, the term “number” shall mean one or an integer greaterthan one (i.e., a plurality).

Unless specifically stated otherwise, as apparent from the discussion,it is appreciated that throughout this specification discussionsutilizing terms such as “processing,” “computing,” “calculating,”“determining” or the like refer to actions or processes of a specificapparatus, such as a special purpose computer or a similar specialpurpose electronic processing/computing device.

What is claimed is:
 1. An image forming apparatus that executes a jobincluding printing an image, the image forming apparatus comprising: aprinter; a detector that detects a first property of a printing papersheet, the printing paper sheet being a paper sheet used by the printerin the printing; and a determinator that, on the basis of the firstproperty detected by the detector and a situation of the job, determinesconditions for executing the printing, wherein: when a differencebetween a second property detected by the detector last time and thefirst property is within a predetermined range, the determinatordetermines the conditions based on the first property and the situation,and when the difference is not within the predetermined range, thedeterminator determines the conditions based on a kind of the printingpaper sheet.
 2. The image forming apparatus according to claim 1,wherein the determinator determines the conditions on the basis of anumber of jobs or a volume of a job that is being executed among thejobs.
 3. The image forming apparatus according to claim 2, furthercomprising: a discriminator that discriminates the kind of the printingpaper sheet on the basis of which section, among sections predeterminedcorresponding to respective kinds of paper sheets, includes the firstproperty detected by the detector, wherein in a case where the number ofjobs and the volume satisfy a predetermined requirement, thedeterminator (i) calculates a correction section in which a lower limitof the section is decreased to determine that the kind of the printingpaper sheet has been most recently discriminated by the discriminator,and (ii) determines the conditions on the basis of the correctionsection.
 4. The image forming apparatus according to claim 3, wherein:the section is a section that defines a range of basic weight, and thepredetermined requirement is that the number of jobs is a predeterminednumber of jobs or more, and the volume is equal to or larger than apredetermined amount.
 5. The image forming apparatus according to claim2, further comprising: a discriminator that discriminates the kind ofthe printing paper sheet on the basis of a section, and the firstproperty detected by the detector, wherein in a case where the number ofjobs and the volume satisfy a predetermined requirement, thedeterminator (i) calculates a correction section in which a lower limitof the section is increased to determine that the kind of the printingpaper sheet has been most recently discriminated by the discriminator,and (ii) determines the conditions on the basis of the correctionsection.
 6. The image forming apparatus according to claim 5, wherein:the section is a section that defines a range of basic weight, and thepredetermined requirement is that the number of jobs is a predeterminednumber of jobs or more, and the volume is smaller than a predeterminedamount.
 7. The image forming apparatus according to claim 2, furthercomprising: a post-processor that staples paper sheets, including theprinting paper sheet on which the image has been printed, processing offorming the paper sheets with punched holes, or processing of foldingthe paper sheets; and a discriminator that discriminates the kind of theprinting paper sheet on the basis of a section, and the first propertydetected by the detector, wherein if the number of jobs is apredetermined number of jobs or more and the volume is a predeterminedamount or more, the determinator calculates a first correction sectionin which a lower limit of the section is further decreased, determinesthe conditions of paper-sheet transport speed on the basis of the firstcorrection section, and determines an upper limit of the number of papersheets that can be subjected to the post-processing at a time on thebasis of the first correction section, if the number of jobs is smallerthan the predetermined number of jobs and the volume is smaller than thepredetermined amount, the determinator calculates the first correctionsection, and determines the conditions for a parameter related to theimage, and for temperature of a fixing part that fixes a toner imagerepresenting the image on a paper sheet, on the basis of the firstcorrection section, and if the number of jobs is the predeterminednumber of jobs or more and the volume is smaller than the predeterminedamount, the determinator calculates a second correction section in whicha lower limit of the section is further decreased, and determinesconditions of the speed on the basis of the second correction section.8. The image forming apparatus according to claim 1, wherein thepredetermined range is defined more widely with an increase in watercontent of the printing paper sheet at the time of detecting the secondproperty.
 9. The image forming apparatus according to claim 1, whereinthe determinator determines the conditions for each of items of: speedat which the printing paper sheet is transported; a parameter related tothe image; and temperature of a fixing part that fixes a toner imagerepresenting the image on the printing paper sheet.
 10. The imageforming apparatus according to claim 1, further comprising: apost-processor that staples printing paper sheets, including theprinting paper sheet on which the image has been printed, forms theprinting paper sheets with punched holes, or folds the printing papersheets, wherein, on the basis of the first property detected by thedetector and the situation, the determinator determines an upper limitof the number of paper sheets that can be stapled, can be formed withpunched holes, or can be folded, all together.
 11. The image formingapparatus according to claim 1, wherein, in a case where a paper feedtray that stores paper sheets is opened and closed, or in a case where apower source of the image forming apparatus is switched on again, thedeterminator determines the conditions.
 12. A condition determinationmethod for determining conditions of printing an image by a printer, theprinting being included in a job, the condition determination methodcomprising: detecting a first property of a printing paper sheet used bythe printer in the printing; and determining conditions for executingthe printing on the basis of the detected first property and a situationof the job, wherein: when a difference between a second propertydetected by the detector last time and the first property is within apredetermined range, the determinator determines the conditions based onthe first property and the situation, and when the difference is notwithin the predetermined range, the determinator determines theconditions based on a kind of the printing paper sheet.
 13. Anon-transitory recording medium storing a computer readable program usedin an image forming apparatus that successively executes jobs, each ofwhich includes printing an image by a printer, the computer readableprogram causing the image forming apparatus to execute: detecting afirst property of a printing paper sheet used by the printer in theprinting; and determining, on the basis of the first property detectedby the detecting and a situation of the job, conditions for executingthe printing, wherein: when a difference between a second propertydetected by the detector last time and the first property is within apredetermined range, the determinator determines the conditions based onthe first property and the situation, and when the difference is notwithin the predetermined range, the determinator determines theconditions based on a kind of the printing paper sheet.